When you retire, if you are a member of a defined-contribution pension fund, as opposed to the rare and endangered defined-benefit fund, you must “buy” a pension with at least two-thirds of your savings, if the accumulated amount is more than R247 500.
This is known as “compulsory annuitisation”, and you only need do it when you require an income; otherwise you can just leave your savings in the fund or transfer the amount to a preservation fund. You can also annuitise any discretionary savings you may have – this is voluntary.